a) Field of the Invention
The present invention relates to a damping positioner, and more particularly to a damping positioner that is used in a headrail track of an automatic roll-up blind and works with an automatic winding mechanism (i.e., torsional spring device), thereby controlling the winding speed of the roll-up blind and the final stop location of the roll-up blind after rolling up the roll-up blind.
b) Description of the Prior Art
There are two kinds of roll-up blinds in the market: a manual roll-up blind, and an automatic roll-up blind.
The manual roll-up blind is provided with a winding mechanism and a loop-shaped cord at a side of the roll-up blind. The loop-shaped cord is pulled repeatedly by both hands to drive the headrail track of the roll-up blind, such that the curtain that is connected with the headrail track can be driven to roll upward or expand downward.
On the other hand, the automatic roll-up blind is provided with an automatic winding mechanism and a stop device at each end of the headrail track, respectively. The headrail track is driven by the automatic winding mechanism, such that the curtain that is connected with the headrail track can be driven to roll upward.
The existing automatic winding mechanism uses primarily the elastic restoration of the torsional spring to drive the headrail track and the connected curtain, such that the curtain can be expanded downward and rolled upward. Firstly, the torsional spring is set up and tightened to a specific position in advance according to the weight of the curtain used, thereby driving the headrail track to rotate and roll up the curtain that is connected with the track successfully. When the curtain is expanded downward, the spring in the headrail track will rotate more tightly. On the contrary, when the spring is loosened, the elastic restoration will drive the headrail track again to rotate to the pre-determined location and roll up the connected curtain, thereby achieving the effect of automatically rolling up the curtain.
According to the above description, the existing automatic winding mechanism uses primarily the torsional spring to drive the headrail track and the connected curtain to rotate. However, if the elastic restoration force of the torsional spring is too large, then the curtain can be easily rolled up too fast, which results in collision and gives out unpleasant noises. Moreover, this collision can damage the blind and hurt a user accidentally. On the contrary, if the elastic restoration force of the torsional spring is too small, then the curtain cannot be rolled up successfully.
Accordingly, how to control the winding speed of the roll-up blind is an issue to be solved for blind manufacturers.